Well bore cleaner construction

ABSTRACT

In the construction of an oil well bore scraping device, a plurality of braided cables each receive cylindrical spooled ends which are swaged onto one or both ends of the cable and then inserted into the cylindrical wiper body and bradded over, leaving the cables extending outwardly from the wiper body.

linited' States Patent 1191 Paramore et a1.

WELL BORE CLEANER CONSTRUCTION Inventors: Edwin L. Paramore; Tom W.Howe,

both of Duncan, Okla.

Assignee: Halliburton Company, Duncan,

Okla. I

Filed: Oct. 31, 1972 Appl. No.: 302,434

US. Cl 166/172, '166/173, 403/194, 1 403/199 Int. Cl E2lb 37/02 Field ofSearch 166/172, 173, 241, 177; 403/193, 194, 199, 274; 24/73 ESReferences Cited UNITED STATES PATENTS 3/1942 Andren et a1 403/193 XPrimaryExaminerH. Hampton Hunter Attorney, Agent, or Firm-John H.Tregoning 5'7] ABSTRACT In the construction of an oil well bore scrapingdevice, a plurality of braided cables each receive cylindrical spooledends which are swaged onto one or both ends of the cable and theninserted into the cylindrical wiper body and bradded over, leaving thecables extending outwardly from the wiper body.

11 Claims, 8 Drawing Figures 1 I WELL BORE CLEANER CONSTRUCTIONBACKGROUND OF THE INVENTION In completing an oil well for production amost critical step involves primary cementing of the well. To simplifythe description of this often complex process, an aqueous cement slurryis placed between the casing and borehole and allowed to harden to bondthe casing to the borehole and provide lateral support for the easingagainst the underground formation. It also provides a permeable annularseal against loss of high pressure gas and/or formation fluids from theunderground formation to the surface via the annular area between thecasing and the borehole wall.

In order for this bonding, sealing, and supporting function to beperformed successfully, good contact must be obtained between the cementslurry and the borehole wall. Thisis often difficult because of thesemi-dry filtercake deposited on the borehole wall from thedrilling mud,which filtercake is not removed when the cement slurry displaces thedrilling mud, and which filtercake undesirably serves to insulate thecement slurry from the borehole wall.

In order to remove this filtercake from the formation, it is known thatplacing abrasive devices on the casing to scratch or scrape the boreholewall as the casing is lowered into the hole will serve to remove theundesirable filtercake.

A common type of wall cleaner has been the cable type such as thoserevealed in U.S. Pat. No. 2,826,253 and US. Pat. No. 3,213,943. Thesedevices consist of a sleeve to be inserted over the casing as it entersthe well. To the sleeve are attached a plurality of looped cables. Thesleeve is fixedly attached to the casing and the cables are arranged toprovide abrasive contact with the bore wall as the casing enters thewell. The casing can be reciprocated while in the well to provide evenfurther cleaning.

The difficulty which arises with the prior art devices is that themethod of attaching the cables or cable loops to the cable sleeve leavesmuch to be desired. Some means of attaching, such as by clamping thecables down on the external surface, results in the cables subsequentlypulling free from the clamps or else they are clamped so tightly thatthey are pinched, and through bending and fatigue will shear and breakloose.

Other means of attaching the cable allow them too much movement suchthat they are not held stiffly against the bore wall surface and,therefore, do not provide adequate scraping and cleaning.

The wall cleaner of the present invention provides a sleeve having stiffdurable cables rigidly and firmly secured in the sleeve and projectingoutward at the optimum angle for maximum cleaning results.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross sectional view ofthe cable and cylindrical spoolprior to their attachment to each other;

F IG. 2 is a cross sectional view of the socket assembly and cable afterattachment;

FIG. 3 is a cross sectional view of the socket assembly and cableinstalled in the sleeve;

FIG. 4 is an isometric view of the cable wall cleaner having staggeredoverlapping cable loops;

FIG. 5 illustrates the apparatus of FIG. 4 in place on a casing stringin a borehole;

FIG. 6 illustrates a second embodiment of the apparatus;

FIG. 7 illustrates a third embodiment of the invention; and

FIG. 7a illustrates the apparatus of FIG. 7 in a collapsed position.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of thepresent invention is disclosed in FIG. 4 in which a cylindrical cablesleeve 10 has openings 11 through the wall thereof capable of receivingsocket assemblies 12 on the ends of cables 13. Preferably, forsimplicity of manufacture and optimum efficiency, sleeve 10 is formedwith two horizontal rows of apertures 11 and each cable loop has one endin the lower row 210 and one end in the upper row 110. In thisembodiment each cable loop spans two apertures and is staggered tooverlap the adjacent cables on each side by one aperture space. Thus, bythis spacing arrangement a complete circumference of cable loops extendoutward around the sleeve 10 while there is maintained sufficient spacebetween the cables 13 and sleeve 10 and between each of the cables toallow proper flow of the removed filter-cake away from the apparatus andup the annulus. The staggered spacing between the cable 13 also preventswear and entanglement between the cables and further provides optimumcement reinforcing qualities when the casing string is cemented.

Referring now to FIGS. 1, 2, and 3, the method of attaching cables 13into sleeve 10 to obtain optimum strength, stiffness, and cable anglewith a minimum of operations is shown.

In assembling the cable loops 13 for attachment into sleeve 10, acylindrical tubular spool 12 is slipped over the end of the braidedmetal cable as shown in FIG. 1 and swaged down tightly as shown in FIG.2 to provide a slip-proof attachment of the end 12 to the cable. Thisresults in the cable socket assembly shown in FIG. 2 This assemblyprocedure is performed on each end of each cable 13.

The remaining cylindrical portion of the socket assembly 12 comprisesthe outermost extended portion of each cable end after it is swagedthereon. This cylindrical portion is then inserted through theappropriate circular aperture 11 in sleeve 10, which apertures are of asize sufficient to allow a relatively snug fit of the socket assemblytherein.

The final step of assembly is the bradding over of the cylindrical end120 protruding inward in sleeve 10 to obtain a permanent, stableattachment to sleeve 10 of the cable and socket assembly.

The bradding over of cylindrical end 120 on the interior surface 150 ofsleeve 10 results in a pulling tight of belled end of socket assembly 12against the outer surface of sleeve 10 and results in the longitudinalaxis of the cable and socket assembly being rigidly held in a postionnormal or perpendicular to the surface of sleeve 10 at that point. Thisresults in the optimum cable angle for scraping the borehole wall whileproviding a strong, wearable connection between the sleeve and thecable.

The cable loop is urged directly out from sleeve 10 in a non-movableposition to provide maximum cable contact with the borehole wall. Therigid non-rotatable connection of the cable in the sleeve helps resistupward or downward movement of the cable and allows greatermaneuverability in reciprocating the casing to obtain more extensivewall cleaning.

The efficient overlapped and staggered placement of the cables 13 onsleeve allows optimum cleaning action with fewer number of cable loopsneeded.

Sleeve 10 is attached to the casing by means such as threaded studs 15extending through sleeve 10 and tightly abutting the casing. While onesuch stud may be used, better attachment can be achieved by using two ormore studs. Alternatively, circumferential casing clamps can be usedabove and below the apparatus to hold it in place on the casing.

FIG. 6 illustrates an alternative method of emplacement of cables on thecasing to obtain a cleaning and scouring effect on the borehole wall. Inthis embodiment instead of using cable loops, short stiff sections ofcable 113 are attached to vertical runners 114 which are in turn held byclamps 115 to the casing in a vertical orientation. One or more of therunners 114 may be positioned on the casing, and cleaning isaccomplished by vertical reciprocation and/or rotation of the casing inthe hole.

It is clear that the looped cable orientation may be used on thevertical runners in place of or in conjunction with the bristle type ofcleaner. This is illustrated in FIG. 6 with vertical runner 214 havinglooped cables 213 attached thereto.

The looped cable configuration is generally preferable for removing thesofter, bulkier filtercake, while the bristle configuration isadvantageous for removing the harder, drier filtercake. Thus, acombination of the two embodiments would be advantageous as a generalallpurpose scraper. The looped and bristled cable cleaners could beplaced in a staggered relationship for optimum effect.

FIG. 7 illustrates a third embodiment utilizing a helical mounting strip314 passing helically around the casing and held in place by easingclamps 315. In this embodiment the stiff bristle type cables 323 or thelooped cables 313 can be attached to the mounting strip by the socketassembly as illustrated in FIGS. 1 through 3. The bristles and loops maybe alternated to obtain a compound scouring action.

FIG. 7a illustrates how the helical cleaner of FIG. 7 can be collapsedfor shipment or storage when not installed on the casing. Anotherdistinct advantage of the helical configuration is the wide range incasing sizes that one such wall cleaner will fit upon and operateeffectively.

Although specific preferred embodiments of the present invention havebeen described in the detailed description above, the description is notintended to limit the invention to the particular forms or embodimentsdisclosed herein since they are to be recognized as illustrative ratherthan restrictive and it will be obvious to those skilled in the art thatthe invention is not so limited. For example, any number of cables orrows of apertures could be utilized with the apparatus of thisinvention. It is also clear that the sleeve can be of any desireddiameter and the length of the cables can be tailored to match both thesleeve size and borehole size. The extension distance of the cables fromthe sleeve can be altered by altering the cables length or by alteringthe spacing between the apertures in the sleeve. Thus, the invention isdeclared to cover all changes and modifications of the specific exampleof the invention herein disclosed for purposes of illustration, which donot constitute departures from the spirit and scope of the invention.

What is claimed is:

1. Apparatus for cleaning well bores of drilling mud filtercake buildupcomprising:

a cylindrical sleeve of generally larger inner diameter than the outerdiameter of casing in the well bore;

said cylindrical sleeve having a plurality of apertures through the wallthereof around the periphery of said sleeve;

a plurality of braided cables;

each end of said braided cable having a bell-ended socket assemblyswaged thereto, and each said bell-ended socket assembly having aninitially cylindrically extending portion extending into one of saidapertures in said sleeve and bradded over on the inside of said sleeve,thereby permanently attaching said cables to said sleeve;

each said cable being of sufficiently greater length than the distancebetween said apertures to which it is connected, thereby forming a stiffoutwardly extending cable loop on the outer surface of said sleeve; and

means for securing said sleeve fixedly to a section of well casing.

2. The apparatus of claim 1 wherein said sleeve has two horizontal,parallel rows of apertures therethrough and each said cable loop has oneend secured through an aperture in one row and the other end secured toan aperture in the other row, with said cable spanning two or moreapertures which are not occupied by that particular cable loop, and withsaid cable loops arranged in a staggered, overlapping arrangement toprovide a full 360' of bore wall contact cable area.

3. A method of constructing a well bore cleaning apparatus comprisingthe steps of:

drilling a plurality of apertures through the wall of a cylindricalsleeve which is adapted to slide over a well casing;

providing a plurality of stiff braided metallic cable lengths; swagingupon each end of each cable length a socket assembly having a flaredmidsection and a cylindrical longitudinally extending end, with saidcylindrical end pointing away from said cable length;

inserting said cylindrical ends of said socket assemblies throughappropriate apertures in said sleeves so as to result in a staggered,over-lapping plurality of looped cables extending outward from saidsleeve; and

bradding said cylindrical ends of said socket assemblies over on theinside surface of said sleeve so as to secure said assembliespermanently in said apertures.

4. A method of attaching generally cylindrical cables to a relativelywide, thin sheet comprising:

forming openings in said sheet to receive said cables;

inserting the end of said cable to be attached to said sheet into atubular sleeve;

swaging said sleeve down on said cable thereby clamping said cablesecurely within said sleeve;

simultaneously forming a belled rib on said sleeve while retaining acylindrical extended end on said sleeve;

inserting said cylindricalend into one of said openings until saidbelled end abuts a surface of said sheet; and

bradding said cylindrical end over on the surface of said sheet oppositefrom the surface abutting said belled end. 5. A wellbore cleaning devicecomprising: means for encircling a casing string in relatively closefitting relationship, said encircling means having a plurality of holesthrough the wall thereof;

attachment means for securing said encircling means to the casingstring;

a plurality of stiff cable means projecting outwardly from saidencircling means; and

means for securing said stiff cable means fixedly to said encirclingmeans, said securing means comprising a plurality of initiallycylindrical sleeves each having a belled end formed by swaging saidsleeve onto said cable means, and each said sleeve passing through oneof said holes and being bradded over on the inside of said encirclingmeans thereby securing each said sleeve to said encircling means inrelatively normal orientation to the surface thereof.

6. The apparatus of claim 5 wherein said encircling means comprises aplurality of vertical bars arranged around the circumference of thecasing and said attachment means comprises one or more circle clampspassing around said vertical bars and said casing and tightly securingsaid bars to said casing. I d

7. The apparatus of claim 5 wherein said encircling means comprises ahelical strip passing helically around the casing and said attachmentmeans comprises one or more circle clamps passing around said helicalstrip and the casing and tightly securing said strip to the casing.

8. The apparatus of claim 5 wherein said encircling means comprises acylindrical sleeve adapted to slide over said casing and said attachmentmeans comprises one or more threaded members passing through said sleevein threaded relationship therewith and arranged to abut the casing andprevent movement of said sleeve with respect to said casing.

9. The apparatus of claim 5 wherein said cable means project straightoutward radially from said encircling means and have one end attached tosaid encircling means, and one end free.

10. The apparatus of claim 5 wherein said cable means comprises aplurality of looped cables having each end thereof secured to saidencircling means and being of sufficient length to form outwardlyextending loops of cable on said encircling means.

11. The apparatus of claim 5 wherein said cable means comprises aplurality of looped cables and a plurality of outwardly straight cablesboth attached tosaid encircling means.

1. Apparatus for cleaning well bores of drilling mud filtercake buildupcomprising: a cylindrical sleeve of generally larger inner diameter thanthe outer diameter of casing in the well bore; said cylindrical sleevehaving a plurality of apertures through the wall thereof around theperiphery of said sleeve; a plurality of braided cables; each end ofsaid braided cable having a bell-ended socket assembly swaged thereto,and each said bell-ended socket assembly having an initiallycylindrically extending portion extending into one of said apertures insaid sleeve and bradded over on the inside of said sleeve, therebypermanently attaching said cables to said sleeve; each said cable beingof sufficiently greater length than the distance between said aperturesto which it is connected, thereby forming a stiff outwardly extendingcable loop on the outer surface of said sleeve; and means for securingsaid sleeve fixedly to a section of well casing.
 2. The apparatus ofclaim 1 wHerein said sleeve has two horizontal, parallel rows ofapertures therethrough and each said cable loop has one end securedthrough an aperture in one row and the other end secured to an aperturein the other row, with said cable spanning two or more apertures whichare not occupied by that particular cable loop, and with said cableloops arranged in a staggered, overlapping arrangement to provide a full360* of bore wall contact cable area.
 3. A method of constructing a wellbore cleaning apparatus comprising the steps of: drilling a plurality ofapertures through the wall of a cylindrical sleeve which is adapted toslide over a well casing; providing a plurality of stiff braidedmetallic cable lengths; swaging upon each end of each cable length asocket assembly having a flared midsection and a cylindricallongitudinally extending end, with said cylindrical end pointing awayfrom said cable length; inserting said cylindrical ends of said socketassemblies through appropriate apertures in said sleeves so as to resultin a staggered, over-lapping plurality of looped cables extendingoutward from said sleeve; and bradding said cylindrical ends of saidsocket assemblies over on the inside surface of said sleeve so as tosecure said assemblies permanently in said apertures.
 4. A method ofattaching generally cylindrical cables to a relatively wide, thin sheetcomprising: forming openings in said sheet to receive said cables;inserting the end of said cable to be attached to said sheet into atubular sleeve; swaging said sleeve down on said cable thereby clampingsaid cable securely within said sleeve; simultaneously forming a belledrib on said sleeve while retaining a cylindrical extended end on saidsleeve; inserting said cylindrical end into one of said openings untilsaid belled end abuts a surface of said sheet; and bradding saidcylindrical end over on the surface of said sheet opposite from thesurface abutting said belled end.
 5. A wellbore cleaning devicecomprising: means for encircling a casing string in relatively closefitting relationship, said encircling means having a plurality of holesthrough the wall thereof; attachment means for securing said encirclingmeans to the casing string; a plurality of stiff cable means projectingoutwardly from said encircling means; and means for securing said stiffcable means fixedly to said encircling means, said securing meanscomprising a plurality of initially cylindrical sleeves each having abelled end formed by swaging said sleeve onto said cable means, and eachsaid sleeve passing through one of said holes and being bradded over onthe inside of said encircling means thereby securing each said sleeve tosaid encircling means in relatively normal orientation to the surfacethereof.
 6. The apparatus of claim 5 wherein said encircling meanscomprises a plurality of vertical bars arranged around the circumferenceof the casing and said attachment means comprises one or more circleclamps passing around said vertical bars and said casing and tightlysecuring said bars to said casing.
 7. The apparatus of claim 5 whereinsaid encircling means comprises a helical strip passing helically aroundthe casing and said attachment means comprises one or more circle clampspassing around said helical strip and the casing and tightly securingsaid strip to the casing.
 8. The apparatus of claim 5 wherein saidencircling means comprises a cylindrical sleeve adapted to slide oversaid casing and said attachment means comprises one or more threadedmembers passing through said sleeve in threaded relationship therewithand arranged to abut the casing and prevent movement of said sleeve withrespect to said casing.
 9. The apparatus of claim 5 wherein said cablemeans project straight outward radially from said encircling means andhave one end attached to said encircling means, and one end free. 10.The apparatus of claim 5 wherEin said cable means comprises a pluralityof looped cables having each end thereof secured to said encirclingmeans and being of sufficient length to form outwardly extending loopsof cable on said encircling means.
 11. The apparatus of claim 5 whereinsaid cable means comprises a plurality of looped cables and a pluralityof outwardly straight cables both attached to said encircling means.